The CSS content property is very useful for generated content in the ::before or ::after speudo-elements. To insert a new line / line break in that content, use the \A escape characters:

				
					
article h2::before {

  content: "Killing \A Me \A Softly";

  white-space: pre-wrap;

}

				
			

White-space property

css content illustration for: White-space property

In order for the new lines to work properly, you also need to set the white-space property to either pre or pre-wrap.